uhm I think that if we look at CC's and VS' success we see that 2v2's and 3v3's are very important. But I do agree that if one is good at 2v2's and 3v3's that doesn't mean one is also great at duels. Though through playing very actively and with possesing talent , vegito has proven that even that is possible, by coming to the finals of the jj2wc3 1v1 tourney(he was only beaten by FS if I remember correctly).
Anyhow 1v1's, 2v2's and 3v3's altogether rock. I suppose 2v2's are really great cuz there u need teamplay and skills. The more the players the bigger the importance of teamplay...